setMessage()如何工作并且每行的声音都发生了变化?
问题描述:
我是新来的Java和声音API在Java中,我已经写了这段代码,我不能理解不同的声音来自不同的行,因为我没有改变代码中的工具。setMessage()如何工作并且每行的声音都发生了变化?
import java.awt.*;
import javax.swing.*;
import javax.sound.midi.*;
import java.util.*;
import java.awt.event.*;
public class BeatBox {
JPanel mainPanel;
ArrayList<JCheckBox> checkboxList;
Sequencer sequencer;
Sequence sequence;
Track track;
JFrame theFrame;
String[] instrumentNames = {"Bass Drum", "Closed Hi-Hat",
"Open Hi-Hat","Acoustic Snare", "Crash Cymbal", "Hand Clap",
"High Tom", "Hi Bongo", "Maracas", "Whistle", "Low Conga",
"Cowbell", "Vibraslap", "Low-mid Tom", "High Agogo",
"Open Hi Conga"};
int[] instruments = {35,42,46,38,49,39,50,60,70,72,64,56,58,47,67,63};
public static void main (String[] args) {
new BeatBox().buildGUI();
}
public void buildGUI() {
theFrame = new JFrame("Cyber BeatBox");
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BorderLayout layout = new BorderLayout();
JPanel background = new JPanel(layout);
background.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
checkboxList = new ArrayList<JCheckBox>();
Box buttonBox = new Box(BoxLayout.Y_AXIS);
JButton start = new JButton("Start");
start.addActionListener(new MyStartListener());
buttonBox.add(start);
JButton stop = new JButton("Stop");
stop.addActionListener(new MyStopListener());
buttonBox.add(stop);
JButton upTempo = new JButton("Tempo Up");
upTempo.addActionListener(new MyUpTempoListener());
buttonBox.add(upTempo);
JButton downTempo = new JButton("Tempo Down");
downTempo.addActionListener(new MyDownTempoListener());
buttonBox.add(downTempo);
Box nameBox = new Box(BoxLayout.Y_AXIS);
for (int i = 0; i < 16; i++) {
nameBox.add(new Label(instrumentNames[i]));
}
background.add(BorderLayout.EAST, buttonBox);
background.add(BorderLayout.WEST, nameBox);
theFrame.getContentPane().add(background);
GridLayout grid = new GridLayout(16,16);
grid.setVgap(1);
grid.setHgap(2);
mainPanel = new JPanel(grid);
background.add(BorderLayout.CENTER, mainPanel);
for (int i = 0; i < 256; i++) {
JCheckBox c = new JCheckBox();
c.setSelected(false);
checkboxList.add(c);
mainPanel.add(c);
} // end loop
setUpMidi();
theFrame.setBounds(50,50,300,300);
theFrame.pack();
theFrame.setVisible(true);
} // close method
public void setUpMidi() {
try {
sequencer = MidiSystem.getSequencer();
sequencer.open();
sequence = new Sequence(Sequence.PPQ,4);
track = sequence.createTrack();
sequencer.setTempoInBPM(120);
} catch(Exception e) {e.printStackTrace();}
} // close method
public void buildTrackAndStart() {
int[] trackList = null;
sequence.deleteTrack(track);
track = sequence.createTrack();
for (int i = 0; i < 16; i++) {
trackList = new int[16];
int key = instruments[i];
for (int j = 0; j < 16; j++) {
JCheckBox jc = (JCheckBox) checkboxList.get(j + (16*i));
if (jc.isSelected()) {
trackList[j] = key;
} else {
trackList[j] = 0;
}
} // close inner loop
makeTracks(trackList);
} // close outer
try {
sequencer.setSequence(sequence);
sequencer.setLoopCount(sequencer.LOOP_CONTINUOUSLY);
sequencer.start();
sequencer.setTempoInBPM(120);
} catch(Exception e) {e.printStackTrace();}
} // close buildTrackAndStart method
public class MyStartListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
buildTrackAndStart();
}
} // close inner class
public class MyStopListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
sequencer.stop();
}
} // close inner class
public class MyUpTempoListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * 1.03));
}
} // close inner class
public class MyDownTempoListener implements ActionListener {
public void actionPerformed(ActionEvent a) {
float tempoFactor = sequencer.getTempoFactor();
sequencer.setTempoFactor((float)(tempoFactor * .97));
}
} // close inner class
public void makeTracks(int[] list) {
for (int i = 0; i < 16; i++) {
int key = list[i];
if (key != 0) {
track.add(makeEvent(144,9,key, 100, i));
track.add(makeEvent(128,9,key, 100, i+1));
}
}
}
public MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {
MidiEvent event = null;
try {
ShortMessage a = new ShortMessage();
a.setMessage(comd, chan, one, two);
event = new MidiEvent(a, tick);
} catch(Exception e) {e.printStackTrace(); }
return event;
}
} // close class
以上是代码,如果有人能告诉我如何setMessage()
的作品,并关注其论据这将是一个很大的帮助,因为我已经看到了所有的文件,我不能够理解。
答
鼓乐器形成一种特殊情况,因为他们没有像钢琴或喇叭那样的特定音调。一个特定的MIDI通道用于传输鼓乐器的播放。在Midi将军,它是频道10,但你会发现合成器,可以编程,以接收任何频道的鼓。
在分配给鼓乐器(也用于特殊的声音效果通常包括在合成器)中,注记和NOTE OFF为音调消息信息的信道的情况下,实际上用于选择滚筒或声音效果会玩。
例如,为了发挥对信道10中的低音鼓乐器,给注记信息如下:使用信道10(编码9)
写35,其为用于声学低音鼓的音符数上面的GM列表。
有关更多详细信息,请参阅[1]:https://www.cs.cmu.edu/~music/cmsip/readings/MIDI%20tutorial%20for%20programmers.html